idk about that one, i understand 70 watt hps arent very hot, its only 70w it couldnt get that hot, but less then a 40 watt cfl i have a feeling that there was another reason why the hps was so much cooler then the cfl bcuz i was running 2 26 watt cfls with hardly any ventilation and the bulbs were cool enough to touch / grab and my avg grow box temp was around 75-76 (26' width x 14' debth x 20' height), then i bumped it up to 6 26 watts and a 4" high velocity fan exhaust and passive intake and my box sat at 80-81 and the bulbs were a little hotter to grab, not unbearable tho